1. Field of the Invention:
This invention relates to a motion picture projection apparatus capable of selective use of two types of motion picture films stored either in an open reel or in a film cartridge having a pressure plate and a reflecting mirror mounted therein.
2. Description of the Prior Art:
Most motion picture projection apparatus which have so far been available employ an open reel for storing and feeding a motion picture film strip. For projection purposes, an open supply reel on which a motion picture film strip to be projected is coiled is first mounted on a reel spindle shaft of the apparatus. The free end of the film strip is then drawn therefrom past the projection station which includes a pressure plate being attached to another spare reel, i.e., take-up reel mounted on its reel spindle shaft. In this arrangement, the film strip is intermittently or continuously transported from the supply reel to the take-up during the projection operations. With such projection apparatus, it frequently happens that during the time between the successive projection operations, the spare take-up reel is lost, or misplace so as to inconvenience the user. Further, the film strip stored as coiled in an open reel is liable to come loose from the coil around the reel because of the elastic property of the film material itself, and furthermore it is subject to decoloration as a result of direct continuous exposure to the ambient light.
Recently various types of cartridges for storing motion picture films have been proposed which have overcome the above mentioned drawbacks and inconvenience. Exemplary of these cartridges are described, for example, in U.S. Pat. Nos. 3,584,941 and No. 3,615,127. The cartridge disclosed therein contains a supply reel and take-up reel in the housing thereof to which respective ends of a motion picture film strip are permanently attached. The housing of the cartridge is provided with a film gate across which the film strip traverses and behind which is mounted a pressure plate associated with a reflecting mirror so that an illumination light beam incident upon the mirror through a winder provided in the housing of the cartridge is reflected therefrom to the film gate to illuminate the film traversing across the film gate. In this manner, images are projected in sequence onto a screen positioned at a distance from the projection apparatus as the film strip is being transported from the supply reel to the take-up reel.
However, such cartridges have several inferior points to open reels in storing and editing the film strip, because of the compact structure of the cartridges which limits the length of the film strip stored therein and which makes it difficult to perform later editing operations. Further, becuase of the high production cost of the cartridge itself, the film stored in a cartridge is consequently more costly than that stored an open reel. Nevertheless, the motion picture photography field was developed no projection apparatus capable of selective use with a film stored in a cartridge and a film stored in an open reel. The presently proposed projection apparatus are designed for use with respective special types of film feeding means. For example, the apparatus designed for use with an open reel assembly cannot use the cartridge, while the apparatus designed for use with a special type of cartridges cannot use different types of cartridges therefrom as well as the open reel assembly. Therefore, it has been the practice in the prior art that each time a different type of films is used, a different type of projection apparatus adapted for use therewith should be employed. In the case of the necessity of projecting in turn films stored in open reels and in cartridges of different types, not only must their respective projectors be used, but also such a projection procedure provides a significant inconvenience to the user. Also, this is very economically disadvantageous.